Review: PlusSound Cloud Nine – A Second View

Disclaimer: PlusSound is an American company that mostly specializes in after-market cables. They however do also have their own portable amplifier the Cloud Nine. I got the amp free of charge for this review.

Cloud Nine

Ever since Nathan reviewed the PlusSound Cloud Nine (CN) I had been dying to hear one. PlusSound got word of that and they decided to send me another Cloud Nine amp for review. At the same time I also got a superb Apollonian+ IEM cable I have been using with the Earwerkz Legend R, an Apollonian+ cable terminated for Audeze that I have been using with my LCD-XC and an Echo+ Interconnect which has been my to go to interconnect since I got it.

When you look at Nathan’s gorgeous pictures of the Cloud Nine, you can immediately see it’s a pretty basic amplifier. It doesn’t have the fancy enclosure of an ALO or CypherLabs amps and it’s more of a back to basics kind of unit. I quite like that approach. The Cloud Nine is a simple looking portable amplifier intended for use with In-Ear Monitors and low and high impedance headphones. The Cloud nice was designed primarily on improving sound quality and pretty much explains why it has such basic but lovely enclosure. The anodized aluminium shielded enclosure, volume knob, and screws are custom made specifically for Cloud Nine.

The Cloud Nine isn’t the smallest of portable amps and it measures about 2.3″ x 4.5″ x 0.95″ and weighs 3.2 oz (without batteries). The CN actually is an 18V (2 x 9V!) battery powered amp. The down side is that you will have to change out the batteries. That means either replacing the stock delivered Duracell or buy rechargeable ones like I did. I have a mixed feeling with the choice for the 9V batteries but the upside is that you get an extremely effective, powerful and clear sounding amplifier in return. I was pleasantly surprised by the durability of the 9V batteries: I expected them to die on me under 10 hours but I’ve listened to it a whole lot and can you believe I’m still on the original set? All 9 volt batteries (Alkanine, NiMH, Lithium) will work with this amplifier and it can run from 20 hours to 80 hours. Expect long battery life, seriously!

A related down side of the Cloud Nine using 9V batteries is that they have to be easily accessible to change them out. To allow this PlusSound decided to use a thumbscrew system on the back and well it looks awful as we’re not used to seeing that on modern day amps. Then again, contrary to Nathan, I found these thumbscrews very easily accessible and easy to use. Sure it doesn’t look stellar and you can’t put the Cloud Nine up straight but it sure is handy.

The Cloud Nine has 3 gain stages (1x/0dB, 5x/10dB, 10x/20dB) and because of it sounds superb with all my gear from my most sensitive custom IEMs to the hardest to drive HE-500 Hifiman. On the inside you’ll find a precision amplifier followed with dual mono operational amplifier integrated circuits in the output stage. I have to admit I have a soft spot for Dual Mono designs. The entire amplifier goes through cryogenic treatment to improve durability and sound quality but I’m not really convinced of the whole cryo treatment myself.

Does it live up to its expectations?

With a power rating of 1.28W into 32 ohm, 1W into 50 ohm, 250mW into 300 ohm and 120mW into 600 ohm you can clearly see the Cloud Nine is no slouch, it’s extremely powerful for a portable amp of its size. Not only is it powerful: THD:~0.0009%!

Lieven is living in Europe and he's the leader of the gang. He's running Headfonia as a side project next to his full time day job in Digital Marketing & Consultancy. He's a big fan of tube amps and custom inear monitors and has published hundreds of product reviews over the years.

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17 Comments

George Lai

I presume those two screws jutting out at the back are for opening to change batteries, so I don’t understand why Nathan said it’s inaccessible. Can you include a couple more pictures on how the battery looks like inside the device? Thanks.

Lofthanza Art

Miguel Garcia-Guzman

Great review, indeed, it complements very well Nathan’s review. Based on your description I think I may get the Cloud Nine or the Vorzüge PURE II . I have a Noble K10 and I am looking for a good amp that works well with the K10. It seems that Nathan likes both the Cloud Nine and the Vorzüge PURE II with the Noble K10.

I have two questions to chose between the Cloud Nine and Vorzüge PURE II

Question1: of the two amps which one pulls the best of the Noble K10? Question 2: I assume that these amps are shielded and there is no problem in using an iPhone for possible wifi/LTE signal interferences in the sound. Is that correct or I will need to use the iPhone in airplane mode to avoid electrical effects on the amps when playing music?

Gabriel Ross

L.and N. If I could please gush for a moment. If not for Headfonia from year to year. I would not have, the set up I have today. Thank you. Mid-Fi I know, but at it’s best :] Forza usb, Fostex A4, Forza ,Cloud nine[as desk top],Forza, L2’s. Have a great 2016.

Joel

Hi, I hope this amp is still open for discussion. The description reminds me a lot of the original Headamp Pico, which I have heard. How similar are the two? If the Cloud has a similar tonality minus the congestion that I did experience with the Pico then it may be something for me to consider. I just loved the way the Pico sounded with female vocals. Thank you.